It is known that internal combustion engines are equipped with a cooling system. The cooling system is generally provided for cooling down the internal combustion engine, as well as other engine fluids, such as for example the exhaust gas in the EGR cooler and/or the lubricating oil in the oil cooler. The cooling system schematically includes a coolant pump that delivers a coolant, typically a mixture of water and antifreeze, from a coolant tank to a plurality of cooling channels internally defined by the engine block and engine head. The coolant pump is generally integrated in the internal combustion engine and is a fixed flow pump including a moving component, typically an impeller, which is accommodated in a seat realized in the engine block and delivers the coolant directly in the cooling channels. The coolant pump is also associated with a thermostatic valve and it is activated or deactivated as a function of the temperature measured by the thermostatic valve.
After passing through these cooling channels, the coolant is directed to the EGR cooler, to the oil cooler and possibly to other heat exchangers of the motor vehicle, such as for example a cabin heater and/or an electric machinery cooler. Finally, the coolant is cooled down in a radiator and routed back into the coolant tank. A problem of these cooling systems is that, due to the ON/OFF switching of the pump, the temperature of the engine is not always optimal and excessive fuel consumption may arise.